To give a flavour, Arendt quotes an insightful point Brecht made about Hitler. She continues:

This is considerably more than most intellectuals understood in 1941, and it is precisely this extraordinary intelligence, breaking like lightening through the rumble of Marxist platitudes, that has made it so difficult for good men to forgive Brecht his sins, or to reconcile themselves to the fact that he could sin and write good poetry."